Problems with rotating machinery (Centrifugal Pump) in FLUENT
 

Hello,

I have some problems when setting up a rotating machinery (Centrifugal Pump) in FLUENT. I have no experience in rotating CFD, and therefore need your help.

When setting up the domain, I simply did a CAD drawing of the fluid inside the pump, with the impeller cut out from it. The mesh was generated using Meshing in ANSYS Workbench. When implementing the mesh into FLUENT it therefore only contains one cell zone.

In FLUENT i set this cell zone as a rotating frame with zero rotating speed, since I dont want the hole domain to rotate, only enable some parts of it to do so (Maybe it can be set to stationary wall?). The wall between the impeller and fluid is set to rotating wall with a rotational velocity of 2700 rpm, while the outer wall is set to rotating wall with zero absolute velocity. The inlet is set to velocity-inlet while the outlet is set to a pressure-outlet.

I've used default values of the rest of the settings.

My problem is that I get a pressure drop in the pump, instead of the expected rise in pressure. This would be the case if the impeller didn't rotate, so therefore I think there is some problems with my settings. On the other hand have I, with help of contour plots, seen that the impeller is rotating.

Can I solve the problem in this way, or do I need to split the domain into several parts? Or is there any other way of dealing with this kind of problem?

Thanks!

Best Regards,

R

cf pump
 

even i am getting a pressure drop instead of a rise.